Why would that be hard? Aside from company politics, what's stopping Shell or Exxon or BP from outfitting their gas stations with EV charging equipment? Clearly they don't see such a move as profitable right now, but as EV adoption increases, that could change.

I'm not saying doing so is trivial; aside from the equipment cost, many/most/all of those stations will also need electrical supply upgrades. But they at least already have the land, and a company like Tesla will have to deal with equipment cost, electrical supply upgrades, and the cost of acquiring land.